1. Field of the Invention
This invention relates to a method for the regulated feed of pulverized fuel for pressurized gasification in an entrained flow gasifier, and a device for implementing the method.
Pulverized fuel means coals of highly varied degrees of carbonization pulverized to the fineness of dust, such as bituminous coals and lignites, pulverized biomasses, cokes produced by thermal pretreatment including petroleum coke but also combustible residues and wastes from industry, domestic sources, and business trades that can be pulverized.
2. The Prior Art
Methods for pressurized gasification of dust-like fuels are known, in which the dust is fed through a pressurized sluice tank to a metering tank at gasification pressure, from which the pulverized fuel is fed through transport lines to the burner of the gasification reactor as a dust-carrier gas suspension with high loading densities between 250 and 450 kg/m3. Entrained flow gasifiers, gasifiers for dust-like fuels, and direct-feed tuyeres for blast furnaces are considered to be gasification reactors.
Any reducing and neutral gases that are free of condensable constituents, for example such as water vapor, and whose content of free oxygen is <6 vol. %, can be used as pressurizing gases for the pressurized sluices. German Patent No. DE-OS 26 54 662, Czech Republic Patent No. CZ 254104, Soviet Union Patent No. SU 170 2183 A1, and German Patent No. DE 28 31 308 C2 may be mentioned here. A problem with this technology is that the amount of dust flowing per unit time must be constant in order to be able to perform reliably in the necessary temperature range for the process of gasification that occurs with an oxidizing medium containing free oxygen. In particular, the discontinuous loading of the metering tank from the pressurized sluices produces pressure fluctuations that have adverse effects on the pressure differential that serves as the driving force for conveying between the metering tank and the burners of the gasification reactor.